Polyvinyl chloride is inherently difficult to ignite. When ignited polyvinyl chloride burns only with difficulty compared with other polymers. Therefore, polyvinyl chloride has been widely used where fire safety is important. An important fire safety concern is that of smoke and gas emission when a polymer is forced to burn. U.S. Pat. No. 4,053,453 discloses rigid vinyl halide polymer compositions containing copper oxalate and amine molybdates that suppress smoke formation when such polymers burn as determined in the NBS Smoke Chamber (ASTM STP 422). However, as determined in the more rigorous Surface Burning Characteristics Of Building Materials test, (ASTM E-84) compounds are desired that suppress flame spread and smoke formation even further, particularly in thicker sections.